I. Field of the Invention
This invention relates generally to the use of catheters in the medical and veterinary arts and specifically to the retrograde administration of blood and other fluids containing pharmacologic or diagnostic agents through inflatable balloon catheters for the purpose of directing such agents backwards through an appropriate vein adjoining obstructed or otherwise unusable arteries which cause jeopardized circulation to vital organs. The invention is particularly directed to a controlled venous retrograde administration of oxygenated blood or other fluids to provide pharmacologic or diagnostic agents to the heart, brain, eye, kidney, liver, adrenals, or other organs with obstructed arteries thereto.
II. Reference to the Prior Art
Retroperfusion techniques for the heart, which are described in the literature, consist of the forceful delivery of arterial oxygenated blood retrogradely to the jeopardized ischemic myocardium through its adjoining coronary venous vessel in a direction opposite to the normal outflow of venous blood through that vein. This arterial blood crosses retrogradely from the coronary venous channels into the tissue capillary circulation, sometimes referred to as microcirculation, to provide blood and nourishment to an underperfused myocardium.
Coronary venous retroperfusion, as a surgical treatment for patients with coronary artery disease, was introduced by C. S. Beck in the 1940's (Beck, C. S.: Revascularization of the Heart, Surgery, Vol. 26, p. 82, 1949). The two-step Beck procedure consisted of creating a surgical shunt from the aorta (arterial blood) to the coronary sinus (venous circulation), and subsequently restricting the coronary sinus to facilitate effective retroperfusion of coronary veins with arterialized blood. However, long-term followup of these experiments demonstrated an unacceptable degree of myocardial and vascular damage which were apparently due to the development of excessive congestion, edema or hemorrhages resulting from interference with the coronary venous drainage, which caused permanent damage to the myocardium and led to chronic congestive failure (Beck, C. S. et al.: Operations for coronary disease, JAMA Vol. 13, pp. 1225-33, 1954). As a result of these considerable drawbacks and difficulties encountered at that time, coupled with rising interest in newly emerging forms of surgical revascularization of coronary arteries as a means for treatment of coronary artery disease, research in coronary sinus retroperfusion diminished.
In the 1960's, research involving surgical retroperfusion was directed at development of a modified Beck procedure consisting of a more regional coronary venous treatment of a particular zone of the heart thus curtailing the potential extent of myocardial damage due to poor coronary vein drainage.
In the 1970's, the present inventors and co-workers thereof developed a clinically oriented concept of synchronized retroperfusion designed to reduce the above hazards of myocardial edema. This was achieved by phasing of shunted arterial blood by pumping it retrogradely into coronary vein during diastole, while allowing coronary venous drainage in systole. Our experimental demonstration of synchronized retroperfusion effectiveness and safety led to renewed interest in research and application of retroperfusion. Thus, we developed a "time sharing" of the coronary veins which permitted a successful synchronized retroperfusion process with unidirectional retrograde delivery of oxygenated blood into the ischemic area, which is followed by normal coronary venous drainage and we proved that such a method could support the acutely ischemic myocardium, restore its function and reduce infarct size. We also proved that pharmacologic agents or regional cooling could be delivered along with the oxygenated blood retroperfusion. However, the need remained for a more direct and effective delivery of drugs or diagnostic materials to ischemic area where they could be absorbed over a specific time period of treatment. The present invention satisfies this need.